module FastFind

# File lib/fast_find.rb, line 18
def find(*paths, ignore_error: true, executor: default_executor, &block)
  block or return enum_for(__method__, *paths, ignore_error: ignore_error, executor: executor)

  results = SizedQueue.new(1024)
  pending = Set.new

  paths.map!(&:dup).each do |path|
    path = path.to_path if path.respond_to? :to_path
    results << [path, safe_stat(path)]
  end
  results << %i[initial finished]
  pending << path_signature(:initial)

  while (result = results.deq)
    path, stat = result

    if stat == :finished
      break if pending.delete(path_signature(path)).empty?

      next
    end

    catch(:prune) do
      yield_entry(result, block) if path.is_a? String

      if stat.is_a?(File::Stat) && stat.directory? && pending.add?(path_signature(path))
        executor.post(path, results) do |path_, results_|
          walk(path_, results_)
        end
      end
    end

    raise stat if stat.is_a?(Exception) && !ignore_error
  end
ensure
  results.close if results
end

# File lib/fast_find.rb, line 14
def prune
  throw :prune
end

# File lib/fast_find.rb, line 84
def error(e)
  [:exception, e]
end

# File lib/fast_find.rb, line 80
def finish(path)
  [path, :finished]
end

# File lib/fast_find.rb, line 88
def path_signature(path)
  [path, path.encoding]
end

# File lib/fast_find.rb, line 100
def safe_stat(path)
  File.lstat(path)
rescue Errno::ENOENT, Errno::EACCES, Errno::ENOTDIR, Errno::ELOOP,
       Errno::ENAMETOOLONG => e
  e
end

# File lib/fast_find.rb, line 76
def stat(entry)
  [entry, safe_stat(entry)]
end

# File lib/fast_find.rb, line 60
def walk(path, results)
  enc = path.encoding == Encoding::US_ASCII ? FS_ENCODING : path.encoding

  # This benchmarks as about 10% faster than Dirs.foreach
  Dir.entries(path, encoding: enc).each do |entry|
    next if (entry == '.') || (entry == '..')

    results << stat(File.join(path, entry))
  end
rescue Errno::ENOENT, Errno::EACCES, Errno::ENOTDIR, Errno::ELOOP,
       Errno::ENAMETOOLONG => e
  results << error(e)
ensure
  results << finish(path)
end

# File lib/fast_find.rb, line 92
def yield_entry(entry, block)
  if block.arity == 2
    block.call(entry[0].dup, entry[1])
  else
    block.call entry[0].dup
  end
end